Movable-stairway latch



'. F. E. BESSLER MOVABLE STAIRWAY LATCH File d May 4, 1925 3Sheets-Sheet 1 Snow r4 00 /l I a July 19, 1927. 1,636,279

F. E. BESSLER MOVABLE STAI RWAY LATCH Filed May 4, 1925 a Sheets-Sheet 2,July 19,1927. 1 3'- F. E. BESSLER v MOVABLE STAIRWAY v LATCH.

Filed May 4, 1925 v 3 Sheets-Sheet 5 314 under, jilfiwlefl Patented July19, 1927.

UNITED STATES Application filed m 4,

The dcvice shown in this application is of that general sort in which astairway is mounted for reciprocation on a hinged panel, the panel beingmounted to swing upwardly and downwardly with respect to a ceilin andthe present invention aims, particularly, to provide novel latchmeansfor controlling the movement of the stairway on the panel, the latchmeans operating automatically and being applicable to other arts.

It is within the province of the disclosure to improve generally and toenhance the utility of devices of that type to which the inventionappertains.

With the above and other objects in view which will appear as thedescription proceeds, the invention resides in the combination andarrangement of parts and in the details of constructionhereinafterdescribed and claimed, it being understood that changes in the preciseembodiment of the invention herein disclosed, may be made within thescope of what is claimed, without departing from the spirit oftheinvention.

In the accompanying drawings I Figure 1 shows in elevation, a deviceprovided with alatch which is constructed in accordance with theinvention, the panel being swung downwardly, and the stairway being sliddownwardly on the panel; Figure 2 is afragmental elevation wherein theparts are shown as they will appear when the panel has been swungupwardly, and

when the stairway has been retracted; Figtatable in the bearing arms 8and 10. Drums ure 3 is a fragmental plan showing a portion of theoperating mechanism; Figure 4 is a. sectional view showing a drum and attendant parts. Figure 5 is an elevation 'disclosing the latch mechanism;Figure 6 is a top plan of the latch mechanism; Figure 7 is an elevationwherein the opposite side of the latch mechanism from that depicted inFigure 5 appears.

The numeral. 1 denotes a support or frame, which may be the ceiling of aroom, the same having an opening 2. The numeral 3 designates a bracketsecured to the frame 1, the bracket comprising a bifurcated bearing arm.8, and bearing arms 10.

The numeral 19 designates a panel mounted for vertical swingingmovement, and hinged at 21 to the bracket 3. Standards 22 are mounted onthe panel 19 near to the lower end thereof, 'Hollowshafts 25 are ro- 26are provided and have hubs 27 receiving drums 29.

1,636,279 PATENT OFFICE.

FRANK E.. BESSLER, OF AKRON, OHIO.

MOVABLE-STAIRWAY LATCH.

19.25. Serial No. 27,910.

the shafts 25.' The hubs 27 of the drums 26 are secured at 28 to.theshafts 25. The drums 26 are'hollow, and into the drums 26, otherdrums 29 project partially, the drums 29 abutting against the hubs 27 ofthe drums 26. The drums 29 are rotatable withrespect to the shafts 25whereon they are mounted. Coiled springs 30 are located within the Theouter ends of the coiled springs 30 are connected at 32 to the drums 29,the inner ends of the springs being connected, as shown at 31, to theshafts 25'.

Brackets 37 are mounted to swin on the shafts 25. Wheels 38 arejournaled on the brackets 37 and on the standards 22. The stiles of astairway39 aremounted toslide on the wheels 38. The stiles of thestairway 39 are supplied with longitudinal guide grooves 40. Thestandards 22 have keepers 41 which are received at their inner ends inthe guide grooves 40. The parts v41 are called keepers, because theyhave a peculiar function in connection with the latch mechanism to bedescribed hereinafter. The brackets 37 carry ribs 42 which. are receivedslid 1 ably in the guide grooves 40 of the stairway 39. The brackets 37are connected a transverse tie 43 extended beneath the slidable stairway39. i

A standard 49 i mounted on the support or frame 1 and carries a pulley50. There is a longitudinal track 51 on the panel 19, near to the lowerend of the panel. A slide 52 is mounted for reciprocation on the track00 51.- A flexible element ,53 is connectedto the slide 52. The flexibleelement 53 is extendedupwardly about the pulley 50 on the standard 49and is wound about the drum 29. One end of a flexible element 54 is 05connected by an anchor 55 to-the stairway 39. The flexible element 54extends backwardly along the stairway 39 and is. wound about the drum26. The flexible elements 54 and 53, are wound, respectively, inopposite directions, about the drums 26 and 29. The structure describedin this paragraph may be. duplicated at each side of the panel 19. v.

On the lower end of one stile of the stairway 39 there is a'casing orframe 56 which isshown in detail in Figures 5, 6 and 7 of the drawings,the casing carrying a bufl'er 57 which comes into play when the panel 19is swung downwardly, and when the stairway 39 is slid downwardly on thepanel, as shown in Figure 1. One side wall of the casing 56 has anoifset wing 58 wherein an opening 59 is fashioned. The numeral 60designates a slide having, as shown in Figure 6, a U- shaped arm 61,which extends inwardly through the opening 59, one end 62 oi the arm 61bearing on the inner surface of the *asing 56. One part of the arm 61forms a shoulder 80 which has functions which will be explainedhereinafter. There is a slot 63 in the casing 56, wherein operates arivet 64: or like projection, carried by the arm 61. A spring brake 65,of curved form, is carried in its intermediate portion on the projection6-1, the curve 01 the spring 65 hearing against one side wall on-thecasing 56, and the ends of the spring bearing on the part 61 of theslide 60. The spring brake 65 operates to hold the slide 60 in anyposition to which it may have been moved, either to the right or to theleft in Figure 6. The numeral 66 designates a bell crank levercomprising a long or first arm 67 and a short or second arm 68. The

long arm 67 of the bell crank lever 66 has an inclined end edge 69 andan inclined lower edge 70 disposed at an angle to each other. The bellcrank lever 66 is fulcrumed on a pin 71 carried by the wing of thecasing 56.. There is a pivot element 72 on the slide 60, and this pivotelement is receivcd movably in an elongated slot 73 formed in the shortarm 68 of the bell crank lever 66. The result of this construction isthat when the bell crank lever 66 is swung upwardly or downwardly,reciprocating movement will be imparted to the slide 60, to the right orto the left in Figure The numeral 7 1 designates a latch having a hook75 and a beveled end 76. The latch 74 is mounted to swing on the pin 71which forms a fulcrum for the bell crank lever 66. The slide 60 carriesa pin or projection 77 rc ceived in a slot 78 formed in thelatch Tel.The latch 7% has angularly disposed edges 79 and 81. The edge 79cooperates with the shoulder 80, hereinbefore alluded to, to limit thedownward swinging movement of the hook end 75 of the latch 74, and theedge 81 cooperates with the upper end of the shoulder 80, to limit theupward swingingmovement of the hook end/T5 of the latch.

These details will be understood readily when Figure 5 of the drawingsis noted. It may be remarked at this point that the hook 75 of the latch74 is adapted to. cooperate with and engage the outer end of the keeper11 carried by the standard 22 on the panel 19. i

The general operation of 'a stairway of he-class described is understoodbythose skilled in the art, but it may be statedthat the panel .19 isswung domiwardly, by any suitable means shown at 85; the stairway .39being slid downwardliyon the panel, into the position shown in Figure 1,when the the stairway 39 is panel 19 is swung downwardly, the flexibleelement 53 is unrolled from the drum 29, the drum 29 rotates withrespect to the shaft 25, and the spring 30 is put under increasedtension. iVhen the stairway 39 slides downwardly on the panel 19, theflexible element 5a rotates the drum 26 in an opposite direction to thatin which the drum 29 was rotated, the shaft 25 being rotatedaccordingly, and "further tension being put into the spring 30, becausethe inner end of the spring 30 is connected as indicated at 31 to theshaft 25. The result is that when the panel 19 is swung dowmvardly, andwhen slid downwardly, as there is considerable tension in the spring 30,so that the spring will react, to aid in the upward swinging movement ofthe panel 19, by way of the flexible element 53, and to aid in thebackward sliding movement of the stairway 69, by way of the flexibleelement 5 1, when the operator attempts to slide the stairway 39backwardly andto swing the panel 19 upwardly.

Referring, now, to the operation of the latch mechanism shown in Figures5, 6 and 7, let it be supposed that the parts are arshown in Figure 1,

l the latch Tl; being engaged with the (eepcr {11, the panel 19 beingswung upwardly from the position shown in lfi igure 1, ind the stairway39, being slid backwartlly, the panel 19 being closed with respect tothe ripening 2 in the frame 1. ilcl'crring to Vigure 5, suppose tlat thepanel 1!) has been swung (jlownwardly smnewhat, and that the stairway 2hhas moved a little way to the left, What c auseslhis movementto the leftwill be explained hereina'ltcr, but let it beassumed at this place thatthe aforesaid movement to the left actually occurs. As the stairway 3%)moves to the left, the short arm 68 of the bell crank lever 66 strikesthe keeper 11 on the standard 22 oi the stairway 39. The lower end ofthe short arm 66 of the bell crank lei er 66 moves to the right inFigure 5 the long arm 67 ot' the bell crank lever swings downwardly, andthe slide 60 carried to the right, because the bell crank lever 66 isilulcrunied at 71 on the wing he of the casing 56, the lower end of thearm 66 of the bell crank lever being connected to the slide 60 by theelement 72. When the slide 60 moves to the right in Figure 5, as aboveexplained, it is held in the position to which it has been movec, due tothe action of the spring brake 65. When the slide 60, moves to theright, the latch 7a is raised, and the hook 7 is carried upwardly out ofthe path of the keeper 1-1, because the pin'77 of the slide 60 isengaged in the slot 78 of the latch 74 above the point wherein the latchis tulcrumed on the pin 71. The stairway i'iged as shown in Figure 5,the hook 75 39 can now slide to the right in Figures 1 and 5,that is,downwardly on the panel 19.

As the stairway 39 slides downwardly, the inclined edge 70 of the longarm 67 of the bell crank lever 66 slides over the keeper 41. Thisoperation causes the long arm 67 of the bell crank lever to swingupwardly, and causes the short arm 68 of the bell crank lever to swingto the left in Figure :3, thereby moving the slide 60 to the left,because the short arm 63 of the bell crank lever is connected at 72 tothe slide. hen the slide 60 moves to the left in Figure 5, as abovedescribed, the pin 77 on the slide 60 is carried to the left in the slot78 of the latch 74, thus permitting the hook end 75 of the latch toswing downwardly, the latch swinging on its pivotal mounting 71. Theparts 66 and 67 are now in the condition of Figure 5, but the lower endof the stairway 39 has been drawn downwardly as in Figure 1, away fromthe keeper 41.

lVhen the stairway 39 is pushed upwardly, the keeper 41 traverses theedge 76 of the latch, the latch 74 swinging upwardly and then droppingdownwardly so that the hook 75 engages the keeper 41 to hold thestairway in the position to which it has been slid, upwardly andbackwardly, on the panel. The latch 74 can swing, as aforesaid, toengage with the keeper 41, because the latch has the slot 78 whichreceives the pin 77, relative movement between the latch and the Y slide60 thus being possible. If it happens that, accidentally or otherwise,the long arm 67 of the bell crank lever 66 has been swung downwardlyfrom the position of Figures 1v and 5, before the stairway 39 has beenslid backwardly on the panel 19, then the edge 69 of the long arm 67 ofthe bell crank lever 66 will first engage with the keeper 41 and restorethe parts to the position of Figure q 5, so that the latch 74 can engagewiththe keeper 41, as hereinbefore described, upon the upward andbackward movement of the stairway 39. The general construction of thelatch mechanism is such that it will hold the stairway 39 againstdownward sliding movement, after the stairway has been slid upwardly onthe panel, the latch mechanism automatically releasing itself from thekeeper 41 when the downward swinging movement of the panel 19 is begun.

It has been stated hereinbefore that the stairway 39 has a slightbackward or upward movement, in order to enable the keeper 41 to engagethe arm 68 of the bell crank lever 66, when the panel 19 is starteddownwardly. The way in which this movement is brought about, will now beexplained.

Suppose that the panel 19 is closed, and that then the panel 19 isstarted downwardly. As soon as the panel 19 starts to swing downwardly,the flexible element 53, the drum 29, the spring 30, the shaft 25, thedrum 26, and the flexible element 54 impart the very slight backwardmovement to the stairway '39 which is necessary to cause the short arm68 of the bell crank lever 66 to engage the keeper 41, as hereinbeforeexplained. Recalling that the latch mechanism is practically full-sizedin Figure 5, and comparing Figureb with Figure 1, it will be obviousthat the backward movement of the stairway 39 is comparatively slight.The stairway 39 does not tend to slide downwardly and interfere with theoperation above described, for the reason that the stairway is carefullybalanced with respect to the hinged connection 21 which carries thepanel19, it being necessary, therearms, the first arm having a longitudinalcam edge, a friction slide cooperating with fore, to swing the panel 19downwardly, to

the frame, a connection between the slide and V the latch, aconnectionbetween the slide and the bell'crank lever, a keeper and meansfor supporting the keeper for engagement with the hook, the second armof the bell crank and the keeper being relatively movable in onedirection to cause engagement between the keeper and the second arm ofthe bell crank lever, and being relatively movable in an oppositedirection to cause engagement between the longitudinal cam edge and thekeeper.

2. A device of the class described, constructed as set forth in claim 1,and further characterized by the fact that the first-specifiedconnection is a lost-motion connection, the latch having an inclined endedge wherewith the keeper engages when relative move ment in thefirst-specified direction takes place, with the keeper external to thehook.

3. A device of the class described, constructed as set forth in claim 1,and further characterized by the fact that the first arm of the bellcrank lever has an inclined end edge wherewith the keeper engages whenrelative movement in the first-specified direction takes place, with thekeeper external to the hook.

In testimony that I claim the foregoing as my own, I have hereto aflixedmy signature,

